1. Field of the Invention
This invention relates to fragrance compositions containing substituted-2,3-dihydrofurans and to the process of augmenting or enhancing the aroma of fragranced compositions or fragranced articles.
2. Description of the Prior Art
The use of synthetic fragrance chemicals has added a new dimension to the art of perfumery. As a result of the development of new synthetic perfume chemicals, perfumers have greater flexibility in developing fragrance formulations and are better able to mimic natural aromas. However, as perfumers become more adept in the use of synthetic materials for the formulation of sophisticated fragrances and developing the subtle nuances typically associated with natural fragrances, there is a growing demand for new synthetic fragrance compounds.
Furan derivatives are known to have desirable fragrance and flavor qualities. For example, ethyl furoate, n-amyl furoate, ethyl furyl beta-hydroxypropionate and furfural are reported as being useful for the formulation of perfumes, cosmetics and soaps. Furfuryl alkyl and aryl ethers are disclosed as flavor enhancers in U.S. Pat. No. 3,940,502.
Tetrahydrofurans are also disclosed to be useful for fragrance applications. U.S. Pat. No. 3,668,134, for example, discloses the use of esters/ethers of tetrahydrofurans as perfumery ingredients for detergent compositions. 3-Oximino-4-oxo-2,5-dimethyltetrahydrofuran is described in U.S. Pat. No. 4,116,982 and disclosed to have a fine caramel-like fragrance making it useful for the manufacture of scents and flavors. 2-Acetonyl-3,5-dimethyl-5-isopropyltetrahydrofuran is disclosed in U.S. Pat. No. 3,470,209 as having a pleasant spicy odor reminiscent of bay and eucalyptus. 2-(1'-Hydroxymethyl-ethyl)-5-methyl-5-vinyltetrahydrofuran is disclosed in U.S. Pat. No. 3,764,567 to be a useful for floral perfumes. In U.S. Pat. No. 3,227,731 carbonates of 1-(alpha-furyl)-2,2-dialkyl-1,3-dihydroxypropanes and 1-(alpha-tetrahydrofuryl)-2,2-dialkyl-1,3-dihydroxypropanes are indicated to be useful in perfume compounding.
2,3-Dihydrofurans having a vinyl group at the 2-position, a lower carboxylate radical at the 4-position and a methyl group at the 5-position have been reported in Chemical Abstracts, Vol. 75, 87758y (1971); Vol. 93, 71095r (1980); Vol. 93, 239112v (1980); and Vol. 94, 15458v (1981). Dihydrofurans of the same general type are also reported by Vinogradov et. al. in Izv. Akad. Nauk SSSR, Ser. Khimm, 1981, (9), 2077-84 and Morlyan et al. in Russian Pat. (Inventor's Certificate) No. 979,346. The compounds of Vinogradov et. al. and Morlyan et. al. are obtained by the oxidative addition of 1,3-dicarbonyl compounds with dienes in acetic acid and in the presence of manganese (III) acetate and copper (II) acetate. Employing a similar reaction procedure, Heiba et. al. (J. Org. Chem., Vol. 39, No. 23, 1974) have prepared and reported 2,3-dihydrofurans having a phenyl group substituted at the 2-position.
Other substituted dihydrofuran derivatives are also described in the prior art. For example, the methyl ester of 2,5-dimethyl-4,5-dihydrofuran-3-carboxylic acid is disclosed in Chemical Abstracts, Vol. 52, 11022c (1958). The preparation of 3-carbethoxy-2-methyl-5-isopropenyl-4,5-dihydrofuran is described in Chemical Abstracts, Vol. 64, 15725b (1966). 4-Carbomethoxy-2,2,5-trimethyl-2,3-dihydrofuran, 4-carbethoxy-2,2,5-trimethyl-2,3-dihydrofuran and 4-carbomethoxy-2-ethyl-2,5-dimethyl-2,3-dihydrofuran are disclosed by R. Verhe et. al. in Tetrahedron, Vol. 38, No. 24, 3649-3666, 1982.